A known opening-and-closing member drive control apparatus for a vehicle is disclosed in, for example, JP3411383B2, JP2007-2589A, JP2504060B2 and JP2002-38796A. For example, according to the opening-and-closing member drive control apparatus for the vehicle disclosed in JP3411383B2, a window glass, serving as the opening-and-closing member, is moved upwardly or downwardly by a driving force of a DC motor, and a driving of the DC motor is controlled so that in a case where an object is sandwiched during the upward or downward movement of the door panel, a sandwiching avoidance process, in which the driving of the DC motor is stopped or the DC motor is rotated in the opposite direction, is executed. The opening-and-closing member drive control apparatus for the vehicle disclosed in JP3411383B2 includes a rotational number detecting means for detecting a rotational number of the DC motor, a rotational torque difference calculating means for calculating a rotational torque difference of the DC motor on the basis of a rotational number difference of the DC motor between the rotational number in an unloaded state and the rotational number in a loaded state, each of which is detected by means of the rotational number detecting means, a determination means for determining whether or not the rotational torque difference, calculated by means of the rotational torque difference calculating means, becomes a predetermined rotational torque difference, and an instruction means for instructing an execution of the sandwiching avoidance process when the rotational torque difference, calculated by means of the rotational torque difference calculating means, becomes the predetermined rotational torque difference. According to the opening-and-closing member drive control apparatus of JP3411383B2, a decreasing degree of the rotational number of the DC motor for determining the sandwiching of the object is determined not in a manner of comparing the rotational number and a threshold value, which is calculated empirically or experimentally, but in a manner of directly calculating a torque (the rotational torque difference) of the DC motor when the sandwiching of the object actually occurs. Therefore, regardless of an assembly state, it may be possible to determine the sandwiching of the object.
However, it is known that a relationship between the rotational number difference of the DC motor and the actual rotational torque difference of the DC motor varies depending on a characteristic of the DC motor that may be affected by a temperature thereof. More specifically, a variation of the rotational torque difference relative to the rotational number difference is small when the DC motor is at a high temperature while the variation of the rotational torque difference relative to the rotational number difference is large when the DC motor is at a low temperature.
Therefore, in a case where the sandwiching of the object is determined on the basis of a relationship between the rotational torque difference of the DC motor, which is calculated on the basis of the rotational number difference of the DC motor, and a predetermined rotational torque difference (the threshold value), the rotational torque difference may be overestimated at the high temperature of the DC motor, and even though the object is not sandwiched, the sandwiching of the object may be mistakenly determined. Further, the rotational torque difference may be underestimated at the low temperature of the DC motor, the determination of the sandwiching may be delayed, and the load at the time of the determination of the sandwiching may become excessive.
A need thus exists for an opening-and-closing member drive control apparatus for a vehicle which is not susceptible to the drawback mentioned above.